U.S. patent application number 14/889108 was filed with the patent office on 2016-06-16 for two-dimensional discrete fourier transform (2d-dft) based codebook for elevation beamforming.
The applicant listed for this patent is Peng CHENG, Jilei HOU, QUALCOMM INCORPORATED, Neng WANG, Chao WEI. Invention is credited to Peng Cheng, Jilei Hou, Neng Wang, Chao Wei.
Application Number | 20160173180 14/889108 |
Document ID | / |
Family ID | 52021564 |
Filed Date | 2016-06-16 |
United States Patent
Application |
20160173180 |
Kind Code |
A1 |
Cheng; Peng ; et
al. |
June 16, 2016 |
TWO-DIMENSIONAL DISCRETE FOURIER TRANSFORM (2D-DFT) BASED CODEBOOK
FOR ELEVATION BEAMFORMING
Abstract
The present disclosure relates to systems and methods for a
two-dimensional discrete Fourier transform based codebook for
elevation beamforming. A two-dimensional discrete Fourier transform
based codebook is determined for elevation beamforming. The
codebook supports single stream codewords and multistream
codewords. The two-dimensional discrete Fourier transform based
codebook is generated by stacking the columns of the matrix product
of two discrete Fourier transform codebook matrices. The codebook
size may be flexibly designed based on required beam resolution in
azimuth and elevation. A best codebook index is selected from the
generated two-dimensional discrete Fourier transform based
codebook. The selected codebook index is provided in a channel
state information report. The channel state information report is
transmitted to a base station.
Inventors: |
Cheng; Peng; (Beijing,
CN) ; Wei; Chao; (Beijing, CN) ; Wang;
Neng; (Beijing, CN) ; Hou; Jilei; (Beijing,
CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CHENG; Peng
WEI; Chao
WANG; Neng
HOU; Jilei
QUALCOMM INCORPORATED |
San Diego
San Diego
San Diego
San Diego
San Diego |
CA
CA
CA
CA
CA |
US
US
US
US
US |
|
|
Family ID: |
52021564 |
Appl. No.: |
14/889108 |
Filed: |
June 12, 2014 |
PCT Filed: |
June 12, 2014 |
PCT NO: |
PCT/CN2014/079735 |
371 Date: |
November 4, 2015 |
Current U.S.
Class: |
375/267 |
Current CPC
Class: |
H04L 27/2628 20130101;
H04B 7/0617 20130101; H04B 7/0417 20130101; H04B 7/0469 20130101;
H04B 7/0478 20130101 |
International
Class: |
H04B 7/04 20060101
H04B007/04; H04L 27/26 20060101 H04L027/26 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 13, 2013 |
CN |
PCT/CN2013/077164 |
Claims
1. A method for channel state information reporting, comprising:
determining a two-dimensional discrete Fourier transform based
codebook for elevation beamforming, wherein the codebook supports
single stream codewords and multistream codewords; generating the
two-dimensional discrete Fourier transform based codebook;
selecting a best codebook index from the generated two-dimensional
discrete Fourier transform based codebook; providing the selected
codebook index in a channel state information report; and
transmitting the channel state information report to a base
station.
2. The method of claim 1, wherein the method is performed by a
wireless communication device.
3. The method of claim 2, wherein the wireless communication device
reports two codebook indexes ic1 and ic2 for a W1 matrix and a W2
matrix.
4. The method of claim 3, wherein the channel state information for
the W1 matrix is built by stacking the columns of the matrix
product of two discrete Fourier transform codebook matrices.
5. The method of claim 3, wherein a codebook size of the W1 matrix
is flexibly designed based on required beam resolution in azimuth
and elevation.
6. The method of claim 3, wherein beams of the W1 matrix are
grouped into multiple groups with a grid of beams from both
elevation and azimuth.
7. The method of claim 6, wherein beam groups are overlapped.
8. The method of claim 6, wherein beam groups are
non-overlapped.
9. The method of claim 6, wherein a wrap around is used.
10. The method of claim 3, wherein the W2 matrix is a co-phasing
matrix.
11. The method of claim 3, wherein a matrix from Rel-10 8Tx is
reused as the W2 matrix.
12. A method for transmission by a base station, comprising:
determining that a wireless communication device will use a
two-dimensional discrete Fourier transform based codebook, wherein
the codebook supports single stream codewords and multistream
codewords; generating a two-dimensional discrete Fourier transform
based codebook; receiving a channel state information report from
the wireless communication device; decoding the channel state
information report; obtaining a codebook index from the decoded
channel state information report; generating a first matrix and a
second matrix based on the codebook index; and performing elevation
beamforming for the wireless communication device in a next
scheduled downlink transmission using the first matrix and the
second matrix.
13. The method of claim 12, wherein the first matrix is a W1 matrix
and the second matrix is a W2 matrix.
14. The method of claim 13, wherein the wireless communication
device reports two codebook indexes ic1 and ic2 for the W1 matrix
and the W2 matrix.
15. The method of claim 14, wherein the two-dimensional discrete
Fourier transform based codebook for the W1 matrix is built by
stacking the columns of the matrix product of two discrete Fourier
transform codebook matrices.
16. The method of claim 14, wherein a codebook size of the W1
matrix is flexibly designed based on required beam resolution in
azimuth and elevation.
17. The method of claim 14, wherein beams of the W1 matrix are
grouped into multiple groups with a grid of beams from both
elevation and azimuth.
18. The method of claim 17, wherein beam groups are overlapped.
19. The method of claim 17, wherein beam groups are
non-overlapped.
20. The method of claim 17, wherein a wrap around is used.
21. The method of claim 14, wherein the W2 matrix is a co-phasing
matrix.
22. The method of claim 14, wherein a matrix from Rel-10 8Tx is
reused as the W2 matrix.
23. An apparatus for channel state information reporting,
comprising: a processor; memory in electronic communication with
the processor; and instructions stored in the memory, the
instructions being executable by the processor to: determine a
two-dimensional discrete Fourier transform based codebook for
elevation beamforming, wherein the codebook supports single stream
codewords and multistream codewords; generate the two-dimensional
discrete Fourier transform based codebook; select a best codebook
index from the generated two-dimensional discrete Fourier transform
based codebook; provide the selected codebook index in a channel
state information report; and transmit the channel state
information report to a base station.
24. The apparatus of claim 23, wherein the apparatus is a wireless
communication device.
25. The apparatus of claim 24, wherein the wireless communication
device reports two codebook indexes ic1 and ic2 for a W1 matrix and
a W2 matrix.
26. The apparatus of claim 25, wherein the channel state
information for the W1 matrix is built by stacking the columns of
the matrix product of two discrete Fourier transform codebook
matrices.
27. The apparatus of claim 25, wherein a codebook size of the W1
matrix is flexibly designed based on required beam resolution in
azimuth and elevation.
28. The apparatus of claim 25, wherein beams of the W1 matrix are
grouped into multiple groups with a grid of beams from both
elevation and azimuth.
29. The apparatus of claim 28, wherein beam groups are
overlapped.
30. The apparatus of claim 28, wherein beam groups are
non-overlapped.
Description
RELATED APPLICATIONS AND PRIORITY CLAIMS
[0001] This application is related to and claims priority from PCT
international application serial number PCT/CN2013/077164 filed
Jun. 13, 2013, for "TWO-DIMENSIONAL DISCRETE FOURIER TRANSFORM
(2D-DFT) BASED CODEBOOK FOR ELEVATION BEAMFORMING."
TECHNICAL FIELD
[0002] The present disclosure relates generally to wireless
communication systems. More specifically, the present disclosure
relates to systems and methods for a two-dimensional discrete
Fourier transform (2D-DFT) based codebook for elevation
beamforming.
BACKGROUND
[0003] Wireless communication systems are widely deployed to
provide various types of communication content such as voice,
video, data, and so on. These systems may be multiple-access
systems capable of supporting simultaneous communication of
multiple terminals with one or more base stations.
[0004] A problem that must be dealt with in all communication
systems is fading or other interference. There may be problems with
decoding the signals received. One way to deal with these problems
is by utilizing beamforming. With beamforming, instead of using
each transmit antenna to transmit a spatial stream, the transmit
antennas each transmit a linear combination of the spatial streams,
with the combination being chosen so as to optimize the response at
the receiver.
[0005] Smart antennas are arrays of antenna elements, each of which
receive a signal to be transmitted with a predetermined phase
offset and relative gain. The net effect of the array is to direct
a (transmit or receive) beam in a predetermined direction. The beam
is steered by controlling the phase and gain relationships of the
signals that excite the elements of the array. Thus, smart antennas
direct a beam to each individual mobile unit (or multiple mobile
units) as opposed to radiating energy to all mobile units within a
predetermined coverage area (e.g., 120.degree.) as conventional
antennas typically do. Smart antennas increase system capacity by
decreasing the width of the beam directed at each mobile unit and
thereby decreasing interference between mobile units. Such
reductions in interference result in increases in
signal-to-interference and signal-to-noise ratios that improve
performance and/or capacity. In power controlled systems, directing
narrow beam signals at each mobile unit also results in a reduction
in the transmit power required to provide a given level of
performance.
[0006] Wireless communication systems may use beamforming to
provide system-wide gains. In beamforming, multiple antennas on the
transmitter may steer the direction of transmissions towards
multiple antennas on the receiver. Beamforming may reduce the
signal-to-noise ratio (SNR). Beamforming may also decrease the
amount of interference received by terminals in neighboring cells.
Benefits may be realized by providing improved beamforming
techniques.
[0007] The use of codebooks allows a wireless communication device
to indicate to a base station the format of channel state
information (CSI) feedback. Different codebooks can provide
different benefits. For example, some codebooks provide increased
payloads, some provide high feedback accuracy and some codebooks
provide low overhead. Benefits may also be realized by using
adaptive codebooks for channel state information (CSI)
feedback.
SUMMARY
[0008] A method for channel state information reporting is
described. A two-dimensional discrete Fourier transform based
codebook is determined for elevation beamforming. The codebook
supports single stream codewords and multistream codewords. The
two-dimensional discrete Fourier transform based codebook is
generated. A best codebook index is selected from the generated
two-dimensional discrete Fourier transform based codebook. The
selected codebook index is provided in a channel state information
report. The channel state information report is transmitted to a
base station.
[0009] The method may be performed by a wireless communication
device. The wireless communication device may report two codebook
indexes ic1 and ic2 for a W1 matrix and a W2 matrix. The channel
state information for the W1 matrix may be built by stacking the
columns of the matrix product of two discrete Fourier transform
codebook matrices. A codebook size of the W1 matrix may be flexibly
designed based on required beam resolution in azimuth and
elevation. Beams of the W1 matrix be grouped into multiple groups
with a grid of beams from both elevation and azimuth. Beam groups
may be overlapped or non-overlapped.
[0010] A wrap around may be used. The W2 matrix may be a co-phasing
matrix. A matrix from Rel-10 8Tx may be reused as the W2
matrix.
[0011] A method for transmission by a base station is also
described. It is determined that a wireless communication device
will use a two-dimensional discrete Fourier transform based
codebook. The codebook supports single stream codewords and
multistream codewords. A two-dimensional discrete Fourier transform
based codebook is generated. A channel state information report is
received from the wireless communication device. The channel state
information report is decoded. A codebook index is obtained from
the decoded channel state information report. A first matrix and a
second matrix are generated based on the codebook index. Elevation
beamforming is performed for the wireless communication device in a
next scheduled downlink transmission using the first matrix and the
second matrix.
[0012] An apparatus for channel state information reporting is also
described. The apparatus includes a processor, memory in electronic
communication with the processor and instructions stored in the
memory. The instructions are executable by the processor to
determine a two-dimensional discrete Fourier transform based
codebook for elevation beamforming. The codebook supports single
stream codewords and multistream codewords. The instructions are
also executable by the processor to generate the two-dimensional
discrete Fourier transform based codebook. The instructions are
further executable by the processor to select a best codebook index
from the generated two-dimensional discrete Fourier transform based
codebook. The instructions are also executable by the processor to
provide the selected codebook index in a channel state information
report. The instructions are further executable by the processor to
transmit the channel state information report to a base
station.
[0013] A base station used for transmitting signals is described.
The base station includes a processor, memory in electronic
communication with the processor and instructions stored in the
memory. The instructions are executable by the processor to
determine that a wireless communication device will use a
two-dimensional discrete Fourier transform based codebook. The
codebook supports single stream codewords and multistream
codewords. The instructions are also executable by the processor to
generate a two-dimensional discrete Fourier transform based
codebook. The instructions are further executable by the processor
to receive a channel state information report from the wireless
communication device. The instructions are also executable by the
processor to decode the channel state information report. The
instructions are further executable by the processor to obtain a
codebook index from the decoded channel state information report.
The instructions are also executable by the processor to generate a
first matrix and a second matrix based on the codebook index. The
instructions are further executable by the processor to perform
elevation beamforming for the wireless communication device in a
next scheduled downlink transmission using the first matrix and the
second matrix.
[0014] An apparatus configured for channel state information
reporting is also described. The apparatus includes means for
determining a two-dimensional discrete Fourier transform based
codebook for elevation beamforming. The codebook supports single
stream codewords and multistream codewords. The apparatus also
includes means for generating the two-dimensional discrete Fourier
transform based codebook. The apparatus further includes means for
selecting a best codebook index from the generated two-dimensional
discrete Fourier transform based codebook. The apparatus also
includes means for providing the selected codebook index in a
channel state information report. The apparatus further includes
means for transmitting the channel state information report to a
base station.
[0015] An apparatus is described. The apparatus includes means for
determining that a wireless communication device will use a
two-dimensional discrete Fourier transform based codebook. The
codebook supports single stream codewords and multistream
codewords. The apparatus also includes means for generating a
two-dimensional discrete Fourier transform based codebook. The
apparatus further includes means for receiving a channel state
information report from the wireless communication device. The
apparatus also includes means for decoding the channel state
information report. The apparatus further includes means for
obtaining a codebook index from the decoded channel state
information report. The apparatus also includes means for
generating a first matrix and a second matrix based on the codebook
index. The apparatus further includes means for performing
elevation beamforming for the wireless communication device in a
next scheduled downlink transmission using the first matrix and the
second matrix.
[0016] A computer-program product including a non-transitory
tangible computer-readable medium having instructions thereon is
also described. The instructions include code for causing a
wireless communication device to determine a two-dimensional
discrete Fourier transform based codebook for elevation
beamforming. The codebook supports single stream codewords and
multistream codewords. The instructions also include code for
causing the wireless communication device to generate the
two-dimensional discrete Fourier transform based codebook. The
instructions further include code for causing the wireless
communication device to select a best codebook index from the
generated two-dimensional discrete Fourier transform based
codebook. The instructions also include code for causing the
wireless communication device to provide the selected codebook
index in a channel state information report. The instructions
further include code for causing the wireless communication device
to transmit the channel state information report to a base
station.
[0017] A computer-program product including a non-transitory
tangible computer-readable medium having instructions thereon is
described. The instructions include code for causing a base station
to determine that a wireless communication device will use a
two-dimensional discrete Fourier transform based codebook. The
codebook supports single stream codewords and multistream
codewords. The instructions also include code for causing the base
station to generate a two-dimensional discrete Fourier transform
based codebook. The instructions further include code for causing
the base station to receive a channel state information report from
the wireless communication device. The instructions also include
code for causing the base station to decode the channel state
information report. The instructions further include code for
causing the base station to obtain a codebook index from the
decoded channel state information report. The instructions also
include code for causing the base station to generate a first
matrix and a second matrix based on the codebook index. The
instructions further include code for causing the base station to
perform elevation beamforming for the wireless communication device
in a next scheduled downlink transmission using the first matrix
and the second matrix
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 shows a wireless communication system;
[0019] FIG. 2 is a diagram illustrating vertical sectorization in a
wireless communication system;
[0020] FIG. 3 is a block diagram illustrating a radio network
operating in accordance with the systems and methods disclosed
herein;
[0021] FIG. 4 is a diagram illustrating two-dimensional antenna
arrays for elevation beamforming;
[0022] FIG. 5 illustrates the possible codebook structures for a
two-dimensional (2D) antenna array;
[0023] FIG. 6 is a block diagram illustrating that grouping of
beams in the W1 matrix;
[0024] FIG. 7 is a block diagram illustrating a two-dimensional
(2D) antenna array;
[0025] FIG. 8 illustrates steering vectors for use in a
two-dimensional discrete Fourier transform (2D-DFT) based codebook
for a wireless communication device;
[0026] FIG. 9 is a flow diagram of a method for channel state
information (CSI) reporting using a two-dimensional discrete
Fourier transform (2D-DFT) based codebook;
[0027] FIG. 10 is a flow diagram of a method for obtaining channel
state information (CSI) reporting using a two-dimensional discrete
Fourier transform (2D-DFT) based codebook;
[0028] FIG. 11 is a block diagram of a transmitter and receiver in
a multiple-input and multiple-output (MIMO) system;
[0029] FIG. 12 illustrates certain components that may be included
within a wireless communication device; and
[0030] FIG. 13 illustrates certain components that may be included
within a base station.
DETAILED DESCRIPTION
[0031] FIG. 1 shows a wireless communication system 100. Wireless
communication systems 100 are widely deployed to provide various
types of communication content such as voice, data and so on. A
wireless communication system 100 may include multiple wireless
devices. A wireless device may be a base station 102 or a wireless
communication device 104. Both a wireless communication device 104
and a base station 102 may be configured to use a two-dimensional
discrete Fourier transform (2D-DFT) based codebook 112a-b for
elevation beamforming.
[0032] A base station 102 is a station that communicates with one
or more wireless communication devices 104. A base station 102 may
also be referred to as, and may include some or all of the
functionality of, an access point, a broadcast transmitter, a
NodeB, an evolved NodeB (eNB), etc. The term "base station" will be
used herein. Each base station 102 provides communication coverage
for a particular geographic area. A base station 102 may provide
communication coverage for one or more wireless communication
devices 104. The term "cell" can refer to a base station 102 and/or
its coverage area, depending on the context in which the term is
used.
[0033] Communications in a wireless communication system 100 (e.g.,
a multiple-access system) may be achieved through transmissions
over a wireless link. Such a communication link may be established
via a single-input and single-output (SISO), multiple-input and
single-output (MISO) or a multiple-input and multiple-output (MIMO)
system. A MIMO system includes transmitter(s) and receiver(s)
equipped, respectively, with multiple (N.sub.T) transmit antennas
and multiple (N.sub.R) receive antennas for data transmission. SISO
and MISO systems are particular instances of a MIMO system. The
MIMO system can provide improved performance (e.g., higher
throughput, greater capacity or improved reliability) if the
additional dimensionalities created by the multiple transmit and
receive antennas are utilized.
[0034] The wireless communication system 100 may utilize MIMO. A
MIMO system may support both time division duplex (TDD) and
frequency division duplex (FDD) systems. In a TDD system, uplink
108 and downlink 106 transmissions are in the same frequency region
so that the reciprocity principle allows the estimation of the
downlink 106 channel from the uplink 108 channel. This enables a
transmitting wireless device to extract transmit beamforming gain
from communications received by the transmitting wireless
device.
[0035] The wireless communication system 100 may be a
multiple-access system capable of supporting communication with
multiple wireless communication devices 104 by sharing the
available system resources (e.g., bandwidth and transmit power).
Examples of such multiple-access systems include code division
multiple access (CDMA) systems, wideband code division multiple
access (W-CDMA) systems, time division multiple access (TDMA)
systems, frequency division multiple access (FDMA) systems,
orthogonal frequency division multiple access (OFDMA) systems,
single-carrier frequency division multiple access (SC-FDMA)
systems, 3.sup.rd Generation Partnership Project (3GPP) Long Term
Evolution (LTE) systems and spatial division multiple access (SDMA)
systems.
[0036] The terms "networks" and "systems" are often used
interchangeably. A CDMA network may implement a radio technology
such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc.
UTRA includes W-CDMA and Low Chip Rate (LCR) while cdma2000 covers
IS-2000, IS-95 and IS-856 standards. A TDMA network may implement a
radio technology such as Global System for Mobile Communications
(GSM). An OFDMA network may implement a radio technology such as
Evolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20,
Flash-OFDMA, etc. UTRA, E-UTRA and GSM are part of Universal Mobile
Telecommunication System (UMTS). Long Term Evolution (LTE) is a
release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS and Long
Term Evolution (LTE) are described in documents from an
organization named "3rd Generation Partnership Project" (3GPP).
cdma2000 is described in documents from an organization named "3rd
Generation Partnership Project 2" (3GPP2).
[0037] The 3.sup.rd Generation Partnership Project (3GPP) is a
collaboration between groups of telecommunications associations
that aims to define a globally applicable 3.sup.rd generation (3G)
mobile phone specification. 3GPP Long Term Evolution (LTE) is a
3GPP project aimed at improving the Universal Mobile
Telecommunications System (UMTS) mobile phone standard. The 3GPP
may define specifications for the next generation of mobile
networks, mobile systems and mobile devices.
[0038] In 3GPP Long Term Evolution (LTE), a wireless communication
device 104 may be referred to as a "user equipment" (UE). A
wireless communication device 104 may also be referred to as, and
may include some or all of the functionality of, a terminal, an
access terminal, a subscriber unit, a station, etc. A wireless
communication device 104 may be a cellular phone, a personal
digital assistant (PDA), a wireless device, a wireless modem, a
handheld device, a laptop computer, etc.
[0039] A wireless communication device 104 may communicate with
zero, one or multiple base stations 102 on the downlink 106 and/or
uplink 108 at any given moment. The downlink 106 (or forward link)
refers to the communication link from a base station 102 to a
wireless communication device 104, and the uplink 108 (or reverse
link) refers to the communication link from a wireless
communication device 104 to a base station 102.
[0040] The use of channel quality indicators (CQI) is an important
component of LTE channel state information (CSI) feedback reporting
that may enable a base station 102 to perform scheduling and
modulation and coding scheme (MCS) selection in a way that reflects
current channel conditions of a wireless communication device 104.
Both the wireless communication device 104 and the base station 102
may use a codebook (a set of pre-agreed parameters) for channel
state information (CSI) reports. The codebook instructs the
receiving device on how to interpret received channel state
information (CSI) reports, including what information is included
in the channel state information (CSI) report and the formatting of
the channel state information (CSI) report.
[0041] The current LTE Rel-8/Rel-10 codebook is designed based on a
one-dimensional (1D) uniform linear array (ULA) antenna array. To
improve transmissions in LTE, elevation beamforming may be applied.
Elevation beamforming refers to the use of a variable elevation
tilt of a transmit signal by a transmit antenna. The performance of
the LTE Rel-8/Rel-10 codebook based on a one-dimensional (1D)
uniform linear array (ULA) antenna array may degrade under
elevation beamforming, due to the use of a two-dimensional (2D)
uniform planar array (UPA) antenna array. Thus, a high-efficiency,
low-overhead codebook is needed for elevation beamforming,
especially for the use of eight-port two-dimensional (2D) uniform
planar array (UPA) antenna arrays 114 that are used in 3GPP.
[0042] Both the wireless communication device 104 and the base
station 102 may include a channel state information (CSI) report
module 110a-b. The channel state information (CSI) report module
110 may be used to transmit and/or receive channel state
information (CSI) reports. Thus, in one configuration the wireless
communication device 104 may use the channel state information
(CSI) report module 110a to generate and transmit a channel state
information (CSI) report to the base station 102 and the base
station 102 may use the channel state information (CSI) report
module 110b to receive and decode a channel state information (CSI)
report from the wireless communication device 104.
[0043] A channel state information (CSI) report module 110 may
include a two-dimensional discrete Fourier transform (2D-DFT) based
codebook 112a-b. The proposed two-dimensional discrete Fourier
transform (2D-DFT) based codebook 112 is well matched with a
two-dimensional (2D) uniform planar array (UPA) antenna array 114
(such as an eight-port antenna array). The two-dimensional discrete
Fourier transform (2D-DFT) based codebook 112 may reuse the LTE R10
8Tx dual codebook structure. The two-dimensional discrete Fourier
transform (2D-DFT) based codebook 112 may support both single
stream codewords and multistream codewords.
[0044] The codebook structure for LTE Rel-10 8Tx (i.e., eight
transmit antennas used by the base station 102) has been defined.
This codebook structure defines a dual codebook structure tailored
to X-pol antenna structures, which is motivated by a preference
from operators and by the large form factor of 8Tx-ULA (uniform
linear array) antenna arrays. The codebook structure for 8Tx
defines a block diagonal grid of beams (GoB) structure W=W1W2. In
the GoB structure, the W1 matrix 120a-b is an 8.times.2Nb matrix
defined as
W 1 = [ X 0 0 X ] . ##EQU00001##
Within the matrix W1 120, X is a 4.times.Nb matrix defining the
grid of beams (GoB) for each polarization, where Nb represents the
number of beams within a beam group. Since the W1 matrix 120 is
reported only for wideband, having multiple overlapping beam groups
per W1 matrix 120 allows the W2 matrix 122a-b to select among the
optimal beams within the beam group on a per-subband basis. The W2
matrix 122 is a 2Nb.times.r matrix. The W2 matrix 122 performs beam
selection within the beam group and co-phasing. In the W2 matrix
122, r denotes the selected transmission rank.
[0045] The use of a two-dimensional discrete Fourier transform
(2D-DFT) based codebook 112 for elevation beamforming may provide
flexibility for joint optimization of elevation and azimuth. The
two-dimensional discrete Fourier transform (2D-DFT) based codebook
112 may also reduce channel state information (CSI) feedback
overhead. The two-dimensional discrete Fourier transform (2D-DFT)
based codebook 112 may include a number of azimuth beam
quantization bits 116a-b and a number of elevation beam
quantization bits 118a-b, which affect the size of the
two-dimensional discrete Fourier transform (2D-DFT) based codebook
112. The codebook size will be discussed below. For quantization
bit selection, the number of quantization bits in the azimuth
domain and the elevation domain may be selected/chosen.
[0046] In a first option, 8 oversampling may be used in both
azimuth and elevation. Since 8 oversampling is used in both azimuth
and elevation, 16 beams can be formed in azimuth and 16 beams can
be formed in elevation (resulting in 256 total beams). If 8 beams
are in each group, and 4 beams overlap with the neighbor group,
there will be a total of 64 groups. In this configuration, a 6-bit
feedback is used for the W1 matrix 120, a 3-bit feedback is used
for the Y matrix 124a-b and a 2-bit feedback is used for the W2
matrix 122, resulting in 11 bits of feedback.
[0047] In a second option, 8 oversampling may be used in azimuth
and 2 oversampling may be used in elevation. There may be 8 beams
per group and 4 beams overlap between consecutive groups. Thus,
there are a total of 16 groups. In this configuration, a 4-bit
feedback is used for the W1 matrix 120, a 3-bit feedback is used
for the Y matrix 124 and a 2-bit feedback is used for the W2 matrix
122, resulting in 9 bits of total feedback.
[0048] In a third option, 4 oversampling may be used in azimuth and
2 oversampling may be used in elevation. There may be 8 beams per
group, and 4 beams overlap between consecutive groups. Thus, there
are a total of 8 groups. In this configuration, a 3-bit feedback is
used for the W1 matrix 120, a 3-bit feedback is used for the Y
matrix 124 and a 2-bit feedback is used for the W2 matrix 122,
resulting in 8 bits of total feedback. The third option uses the
same codebook size as the current R10 8Tx codebook.
[0049] In a fourth option, 4 oversampling may be used in azimuth
and 2 oversampling may be used in elevation. There may be 4 beams
per group, and 2 beams overlap between consecutive groups. Thus,
there are a total of 16 groups. In this configuration, a 4-bit
feedback is used for the W1 matrix 120, a 2-bit feedback is used
for the Y matrix 124 and a 2-bit feedback is used for the W2 matrix
122, resulting in 8 bits of total feedback. The fourth option also
uses the same codebook size as the current R10 8Tx codebook.
[0050] The codebook size of the W1 matrix 120 can be flexibly
designed based on the required beam resolution in azimuth and
elevation. The beams of the W1 matrix 120 may be grouped into
multiple groups with a grid of beams (GoB) from both elevation and
azimuth. The W1 matrix 120 may be a new discrete Fourier transform
(DFT) matrix for a 2.times.2 uniform planar array (UPA) that
includes a total of N.times.M discrete Fourier transform (DFT)
beams. The W2 matrix 122 may be a co-phasing matrix.
[0051] One advantage of using a two-dimensional discrete Fourier
transform (2D-DFT) based codebook 112 is that it provides
flexibility for joint optimization of elevation and azimuth.
Another advantage of using a two-dimensional discrete Fourier
transform (2D-DFT) based codebook 112 is that it reduces channel
state information (CSI) feedback overhead. Using the
two-dimensional discrete Fourier transform (2D-DFT) based codebook
112 may provide a performance gain of approximately 8%-10% over the
LTE 8Tx dual codebook with the same codebook size. The
two-dimensional discrete Fourier transform (2D-DFT) based codebook
112 may reuse the LTE Release-10 dual-codebook structure; thus the
two-dimensional discrete Fourier transform (2D-DFT) based codebook
112 may be more easily accepted by 3GPP.
[0052] FIG. 2 is a diagram illustrating vertical sectorization in a
wireless communication system. The wireless communication system
may include a first base station (eNB-A) 202a and a second base
station (eNB-B) 202b. The wireless communication system may also
include a first wireless communication device (UE-A1) 204a and a
second wireless communication device (UE-A2) 204b that communicate
with the first base station (eNB-A) 202a. The wireless
communication system may further include a third wireless
communication device (UE-B2) 204c and a fourth wireless
communication device (UE-B1) 204d that communicate with the second
base station (eNB-B) 202b.
[0053] To improve transmissions in LTE, horizontal/vertical
beamforming may be applied. The use of 3D-MIMO technology may
greatly improve system capacity by using a two-dimensional antenna
array with a large number of antennas at the base station 202 and a
high beamforming gain. The associated physical downlink control
channel (PDCCH) grant may be mapped to UE-specific search space.
The first base station 202a (i.e., the serving eNB) may broadcast a
common channel state information reference signal (CSI-RS) to all
wireless communication devices 204. This allows the wireless
communication devices 204 to select the best horizontal/vertical
beam 226a-d from a set of fixed beams 226. Each horizontal/vertical
beam 226 may be mapped to a preamble. The mapping of the preamble
to the fixed horizontal/vertical beams 226 may be predefined so
that the wireless communication device 204 knows the preamble after
selecting the horizontal/vertical beam 226. The 3D-MIMO technology
could greatly improve system capacity by using a two-dimensional
antenna array with a large number of antennas at the base station
202, so as to achieve very small intra-cell interference and very
high beamforming gain.
[0054] The first wireless communication device (UE-A1) 204a may be
located within the cell interior 228a of the first base station
(eNB-A) 202a, while the second wireless communication device
(UE-A2) 204b is located on the cell edge 230a of the first base
station (eNB-A) 202a. Likewise, the fourth wireless communication
device (UE-B1) 204d may be located within the cell interior 228b of
the second base station (eNB-B) 202b, while the third wireless
communication device (UE-B2) 204c is located on the cell edge 230b
of the second base station (eNB-B) 202b. Vertical sectorization
using a 2D antenna array allows the first base station (eNB-A) 202a
to create two vertical sectors, (the first beam 226a and the second
beam 226b) rather than one azimuth sector. Likewise, the second
base station (eNB-B) 202b may also create two vertical sectors (the
third beam 226c and the fourth beam 226d). Horizontal sectorization
may also be performed using the 2D antenna array.
[0055] FIG. 3 is a block diagram illustrating a radio network
operating in accordance with the systems and methods disclosed
herein. A wireless communication device 304 may send a channel
state information (CSI) report 336 in an uplink symbol 334 to a
base station 302. In one configuration, the uplink symbol 334 is
sent on a physical uplink shared channel (PUSCH) or a physical
uplink control channel (PUCCH) 332.
[0056] The uplink symbol 334 may include channel state information
(CSI) that may be used by the base station 302 to schedule wireless
transmissions. In one configuration, the uplink symbol 334 may
include a channel state information (CSI) report 336. The channel
state information (CSI) report 336 may include a combination of
channel quality indicator (CQI) 342 information, precoding matrix
indicator (PMI) information (i.e., the codebook index ic1 338a and
the codebook index ic2 338b) and rank indicator (RI) 340
information. The rank indicator (RI) 340 may indicate the number of
layers that can be supported on a channel (e.g., the number of
layers that the wireless communication device 304 can distinguish).
Spatial multiplexing (in a MIMO transmission, for example) can be
supported only when the rank indicator (RI) 340 is greater than 1.
The precoding matrix indicator (PMI) may indicate a precoder out of
a codebook (e.g., pre-agreed parameters) that the base station 302
may use for data transmission over multiple antennas based on the
evaluation by the wireless communication device 304 of a received
reference signal.
[0057] Similar to the Rel-10 8Tx codebook, in the two-dimensional
discrete Fourier transform (2D-DFT) based codebook 112, the
wireless communication device 304 will report a first codebook
index ic1 338a and a second codebook index ic2 338b for the W1
matrix 120 and the W2 matrix 122. The W1 matrix 120 is a new
discrete Fourier transform (DFT) matrix for a 2.times.2 uniform
planar array (UPA) that includes a total of N.times.M discrete
Fourier transform (DFT) beams. The W2 matrix 122 is a co-phasing
matrix. The same W2 matrix 122 as used in the R10 8Tx codebook may
be reused as the W2 matrix 122.
[0058] FIG. 4 is a diagram illustrating two-dimensional (2D)
antenna arrays 444 for elevation beamforming. There are four types
of two-dimensional (2D) uniform planar array (UPA) antenna arrays
444 that have 8 ports. In the two 2.times.4 configurations (which
are capable of reusing the R10 8TX codebook), the R10 8Tx codebook
may be reused. However, the 4.times.2 configurations (444a and
444b) require the use of a new codebook (i.e., the two-dimensional
discrete Fourier transform (2D-DFT) based codebook 112 defined
herein). In both of the two-dimensional (2D) uniform planar array
(UPA) antenna arrays 444 shown, dx may be equal to 0.5.lamda., dy
may be equal to 2.0.lamda., and dz may be equal to 4.0.lamda.,
where .lamda. represents the wavelength.
[0059] FIG. 5 illustrates the possible codebook structures for a
two-dimensional (2D) antenna array. The codebook structure for a
two-dimensional discrete Fourier transform (2D-DFT) based codebook
112 is a unified codebook. In a composite product codebook, the
matrix W=W.sub.H.times.(I.sub.NHW.sub.V), where the W.sub.H matrix
546 and the W.sub.V matrix 548 are two codebooks for a subarray
with cell specific aggregation. In contrast, in a unified dual
codebook (i.e., a two-dimensional discrete Fourier transform
(2D-DFT) based codebook 112), W=W1W2, where the W1 matrix 520=[X 0;
0 Y] is block diagonal and the W2 matrix 522 is a 2.times.2
co-phasing matrix. Both the W1 matrix 520 and the W2 matrix 522 of
the unified dual codebook are fully compatible with R10. The
unified codebook provides flexibility for joint optimization of
elevation and azimuth and to reduce the channel state information
(CSI) feedback overhead.
[0060] FIG. 6 is a block diagram illustrating that grouping of
beams in the W1 matrix 120. Beams in the W1 matrix 120 may be
grouped in multiple groups with a grid of beams (GOB) 650 from both
elevation and azimuth. The groups may be overlapped in both
elevation and azimuth. A grid of beams (GOB) 650 of four may be
used in each group. A wrap around may also be used.
[0061] Similar to Rel-10 8Tx, the wireless communication device 104
may report a first codebook index i.sub.c1 338a and a second
codebook index i.sub.c2 338b for the W.sub.1 matrix 120 and the
W.sub.2 matrix 122, where the W.sub.1 matrix 120 is a new discrete
Fourier transform (DFT) matrix for a 2.times.2 uniform planar array
(UPA) that includes a total of N.times.M discrete Fourier transform
(DFT) beams, the W.sub.2 matrix 122 is a co-phasing matrix (the
same matrix as used in R10 8Tx can be reused as the W.sub.2 matrix
122).
[0062] FIG. 7 is a block diagram illustrating a two-dimensional
(2D) antenna array 752. The two-dimensional (2D) antenna array 752
shown is an 8.times.8 array with uniform antennas. Both azimuth and
elevation elements may be active with individual transmitters and
power amplifiers.
[0063] FIG. 8 illustrates steering vectors for use in a
two-dimensional discrete Fourier transform (2D-DFT) based codebook
112 for a wireless communication device 804. The two-dimensional
discrete Fourier transform (2D-DFT) based codebook 112 may be a
unified codebook (as discussed above in relation to FIG. 5).
[0064] For an N.times.M two-dimensional uniform planar array
(2D-UPA), the steering vector in the azimuth domain is given by
Equation (1):
a r ( .PHI. , .theta. ) = [ 1 - j 2 .pi. .lamda. d a cos ( .PHI. )
sin ( .theta. ) - j 2 .pi. .lamda. d a ( N - 1 ) cos ( .PHI. ) sin
( .theta. ) ] T = [ - j 2 .pi. .mu. - j 2 .pi. ( N - 1 ) .mu. ] T .
( 1 ) ##EQU00002##
[0065] In Equation (1),
.mu. = 1 .lamda. d a cos ( .PHI. ) sin ( .theta. ) .
##EQU00003##
The variables d.sub.a 858, .phi. 860 and .theta. 854 of Equation
(1) are illustrated in FIG. 8. For an N.times.M two-dimensional
uniform planar array (2D-UPA), the steering vector in the elevation
domain is given by Equation (2):
a c ( .PHI. , .theta. ) = [ 1 - j 2 .pi. .lamda. d e sin ( .PHI. )
sin ( .theta. ) - j 2 .pi. .lamda. d e ( M - 1 ) sin ( .PHI. ) sin
( .theta. ) ] T = [ 1 - j 2 .pi. v - j 2 .pi. ( M - 1 ) v ] T . ( 2
) ##EQU00004##
[0066] In Equation (2),
v = 1 .lamda. d e sin ( .PHI. ) sin ( .theta. ) . ##EQU00005##
The variable d.sub.e 856 of Equation (2) is illustrated in FIG. 8.
From Equation (1) and Equation (2), the combined steering vector
may be described using Equation (3):
A ( .PHI. , .theta. ) = vec ( a r ( .PHI. , .theta. ) a c ( .PHI. ,
.theta. ) T ) = vec ( a r ( .mu. ) a c ( v ) T ) = [ 1 - j 2 .pi. v
- j 2 .pi. ( M - 1 ) v - j2 .pi. .mu. - j2 .pi. ( .mu. + v ) - j2
.pi. [ .mu. + ( M - 1 ) v ] - j2.pi. ( N - 1 ) .mu. - j2 .pi. [ ( N
- 1 ) .mu. + ( M - 1 ) v ] ] T ( 3 ) ##EQU00006##
[0067] An (N, M) two-dimensional discrete Fourier transform
(2D-DFT) matrix W can be described using Equation (4):
w ( n , m ) = 1 NM [ 1 - j2.pi. 1 m - j2.pi. ( M - 1 ) m - j2 .pi.
1 n - j 2 .pi. [ 1 n + 1 m ] - j 2 .pi. [ 1 n + ( M - 1 ) m ] - j 2
.pi. [ ( N - 1 ) n ] - j [ ( N - 1 ) n + ( M - 1 ) m ] ] ( 4 )
##EQU00007##
[0068] In Equation (4),
n = 0 , 1 N , 2 N , , N - 1 N , m = 0 , 1 M , 2 M , , M - 1 M .
##EQU00008##
Comparing Equation (3) and Equation (4), the steering vector can be
represented using Equation (4) by uniformly quantizing the azimuth
vector
.mu. = d a cos ( .PHI. ) sin ( .theta. ) .lamda. ##EQU00009##
with n and the elevation vector
v = d e sin ( .PHI. ) sin ( .theta. ) .lamda. ##EQU00010##
with m. This allows for the building of the codebook for a
two-dimensional (2D) uniform planar array (UPA) antenna array with
a two-dimensional (2D) discrete Fourier transform (DFT) matrix.
[0069] Similarly, the two-dimensional discrete Fourier transform
(2D-DFT) based codebook 112 for a two-dimensional (2D) uniform
planar array (UPA) antenna array may be built by stacking the
columns of the matrix product of the azimuth codebook and the
elevation codebook. It may be assumed that the azimuth discrete
Fourier transform (DFT) codebook is
B.sub.a={c.sub.0.sup.a,c.sub.1.sup.a, . . . ,c.sub.P-1.sup.a} and
the elevation discrete Fourier transform (DFT) codebook is
B.sub.e={c.sub.0.sup.e,c.sub.1.sup.e, . . . ,c.sub.Q-1.sup.e}.
Thus, the two-dimensional discrete Fourier transform (2D-DFT) based
codebook 112 may be defined as B={c.sub.0,c.sub.1, . . . ,c.sub.l,
. . . ,c.sub.PQ-1}, where
c.sub.l=vec[c.sub.p.sup.a(c.sub.q.sup.e).sup.T] and p=floor(l/Q),
q=mod(l,Q).
[0070] A metric defined as
g ( .PHI. , .theta. ) = max m f m T a ( .PHI. , .theta. ) 2
##EQU00011##
may be used to illustrate the codebook gain in a two-dimensional
discrete Fourier transform (2D-DFT) based codebook 112. In the
metric, f.sub.m is the codeword and a(.phi.,.theta.) is the
steering vector of the two-dimensional (2D) uniform planar array
(UPA) antenna array. From the comparison, the two-dimensional
discrete Fourier transform (2D-DFT) based codebook 112 is shown to
be better matched with a two-dimensional (2D) uniform planar array
(UPA) antenna array than the LTE codebook.
[0071] FIG. 9 is a flow diagram of a method 900 for channel state
information (CSI) reporting using a two-dimensional discrete
Fourier transform (2D-DFT) based codebook 112. The method 900 may
be performed by a wireless communication device 104. In one
configuration, the wireless communication device 104 may provide
channel state information (CSI) reports 336 that correspond to an
eight-port two-dimensional (2D) uniform planar array (UPA) antenna
array.
[0072] The wireless communication device 104 may determine 902 a
two-dimensional discrete Fourier transform (2D-DFT) based codebook
112 for elevation beamforming. For example, the wireless
communication device 104 may decide to use a two-dimensional
discrete Fourier transform (2D-DFT) based codebook 112 or a base
station 102 may notify the wireless communication device 104 to use
a two-dimensional discrete Fourier transform (2D-DFT) based
codebook 112 (e.g., through radio resource control (RRC)
signaling). The two-dimensional discrete Fourier transform (2D-DFT)
based codebook 112 used by the wireless communication device 104
may be predefined.
[0073] The wireless communication device 104 may generate 904 a
two-dimensional discrete Fourier transform (2D-DFT) based codebook
112 using the approach described above. The wireless communication
device 104 may then select 906 the best codebook index (ic1 338a
and ic2 338b) from the generated two-dimensional discrete Fourier
transform (2D-DFT) based codebook 112. The wireless communication
device 104 may provide 908 the selected codebook index 338 in a
channel state information (CSI) report 339 as the PMI feedback. The
wireless communication device 104 may then transmit 910 the channel
state information (CSI) report 336 to a base station 102 (i.e.,
feedback the channel state information (CSI) report 336 in the
PUSCH/PUCCH 332).
[0074] FIG. 10 is a flow diagram of a method 1000 for obtaining
channel state information (CSI) reporting using a two-dimensional
discrete Fourier transform (2D-DFT) based codebook 112. The method
1000 may be performed by a base station 102. In one configuration,
the base station 102 may use a two-dimensional (2D) uniform planar
array (UPA) antenna array for transmissions to a wireless
communication device 104.
[0075] The base station 102 may determine 1002 that the wireless
communication device 104 will use a two-dimensional discrete
Fourier transform (2D-DFT) based codebook 112. In one
configuration, the base station 102 may inform the wireless
communication device 104 to use a two-dimensional discrete Fourier
transform (2D-DFT) based codebook 112 (e.g., through RRC
signaling). In another configuration, the base station 102 may
obtain notification from the wireless communication device 104 that
the wireless communication device 104 will use a two-dimensional
discrete Fourier transform (2D-DFT) based codebook 112.
[0076] The base station 102 may generate 1004 a two-dimensional
discrete Fourier transform (2D-DFT) based codebook 112 as described
above. The base station 102 may receive 1006 a channel state
information (CSI) report 336 from the wireless communication device
104. The channel state information (CSI) report 336 may be received
on the PUSCH/PUCCH 332. The base station 102 may decode 1008 the
channel state information (CSI) report 336. The base station 102
may obtain 1010 the codebook index (ic1 338a and ic2 338b) from the
decoded channel state information (CSI) report 336. Decoding
channel state information (CSI) reports 336 is the common channel
state information (CSI) decoding procedure. The base station 102
may generate 1012 the matrix W1 122 and the matrix W2 120 based on
the codebook index 338 feedback from the wireless communication
device 104. The base station 102 may then perform 1014 elevation
beamforming for the wireless communication device 104 in the next
scheduled downlink transmission using the matrix W1 120 and the
matrix W2 122.
[0077] FIG. 11 is a block diagram of a transmitter 1171 and
receiver 1172 in a multiple-input and multiple-output (MIMO) system
1170. In the transmitter 1171, traffic data for a number of data
streams is provided from a data source 1173 to a transmit (TX) data
processor 1174. Each data stream may then be transmitted over a
respective transmit antenna 1177a through 1177t. The transmit (TX)
data processor 1174 may format, code, and interleave the traffic
data for each data stream based on a particular coding scheme
selected for that data stream to provide coded data.
[0078] The coded data for each data stream may be multiplexed with
pilot data using OFDM techniques. The pilot data may be a known
data pattern that is processed in a known manner and used at the
receiver 1172 to estimate the channel response. The multiplexed
pilot and coded data for each stream is then modulated (i.e.,
symbol mapped) based on a particular modulation scheme (e.g.,
binary phase shift keying (BPSK), quadrature phase shift keying
(QPSK), multiple phase shift keying (M-PSK) or multi-level
quadrature amplitude modulation (M-QAM)) selected for that data
stream to provide modulation symbols. The data rate, coding and
modulation for each data stream may be determined by instructions
performed by a processor.
[0079] The modulation symbols for all data streams may be provided
to a transmit (TX) multiple-input multiple-output (MIMO) processor
1175, which may further process the modulation symbols (e.g., for
OFDM). The transmit (TX) multiple-input multiple-output (MIMO)
processor 1175 then provides NT modulation symbol streams to NT
transmitters (TMTR) 1176a through 1176t. The transmit (TX)
multiple-input multiple-output (MIMO) processor 1175 may apply
beamforming weights to the symbols of the data streams and to the
antenna 1177 from which the symbol is being transmitted.
[0080] Each transmitter 1176 may receive and process a respective
symbol stream to provide one or more analog signals, and further
condition (e.g., amplify, filter and upconvert) the analog signals
to provide a modulated signal suitable for transmission over the
multiple-input and multiple-output (MIMO) channel. NT modulated
signals from transmitters 1176a through 1176t are then transmitted
from NT antennas 1177a through 1177t, respectively.
[0081] At the receiver 1172, the transmitted modulated signals are
received by NR antennas 1182a through 1182r and the received signal
from each antenna 1182 is provided to a respective receiver (RCVR)
1183a through 1183r. Each receiver 1183 may condition (e.g.,
filter, amplify and downconvert) a respective received signal,
digitize the conditioned signal to provide samples, and further
process the samples to provide a corresponding "received" symbol
stream.
[0082] An RX data processor 1184 then receives and processes the NR
received symbol streams from NR receivers 1183 based on a
particular receiver processing technique to provide NT "detected"
symbol streams. The RX data processor 1184 then demodulates,
deinterleaves and decodes each detected symbol stream to recover
the traffic data for the data stream. The processing by RX data
processor 1184 is complementary to that performed by TX
multiple-input and multiple-output (MIMO) processor 1175 and TX
data processor 1174 at transmitter system 1171.
[0083] A processor 1185 may periodically determine which pre-coding
matrix to use. The processor 1185 may store information on and
retrieve information from memory 1186. The processor 1185
formulates a reverse link message comprising a matrix index portion
and a rank value portion. The reverse link message may be referred
to as channel state information (CSI). The reverse link message may
comprise various types of information regarding the communication
link and/or the received data stream. The reverse link message is
then processed by a TX data processor 1188, which also receives
traffic data for a number of data streams from a data source 1189,
modulated by a modulator 1187, conditioned by transmitters 1183a
through 1183r, and transmitted back to the transmitter 1171.
[0084] At the transmitter 1171, the modulated signals from the
receiver 1172 are received by antennas 1177, conditioned by
receivers 1176, demodulated by a demodulator 1179, and processed by
an RX data processor 1180 to extract the reverse link message
transmitted by the receiver system 1172. A processor 1181 may
receive channel state information (CSI) from the RX data processor
1180. The processor 1181 may store information on and retrieve
information from memory 1178. The processor 1181 then determines
which pre-coding matrix to use for determining the beamforming
weights and then processes the extracted message.
[0085] FIG. 12 illustrates certain components that may be included
within a wireless communication device 1204. The wireless
communication device 1204 may be an access terminal, a mobile
station, a user equipment (UE), etc. The wireless communication
device 1204 includes a processor 1203. The processor 1203 may be a
general purpose single- or multi-chip microprocessor (e.g., an
ARM), a special purpose microprocessor (e.g., a digital signal
processor (DSP)), a microcontroller, a programmable gate array,
etc. The processor 1203 may be referred to as a central processing
unit (CPU). Although just a single processor 1203 is shown in the
wireless communication device 1204 of FIG. 12, in an alternative
configuration, a combination of processors (e.g., an ARM and DSP)
could be used.
[0086] The wireless communication device 1204 also includes memory
1205. The memory 1205 may be any electronic component capable of
storing electronic information. The memory 1205 may be embodied as
random access memory (RAM), read-only memory (ROM), magnetic disk
storage media, optical storage media, flash memory devices in RAM,
on-board memory included with the processor, EPROM memory, EEPROM
memory, registers, and so forth, including combinations
thereof.
[0087] Data 1207a and instructions 1209a may be stored in the
memory 1205. The instructions 1209a may be executable by the
processor 1203 to implement the methods disclosed herein. Executing
the instructions 1209a may involve the use of the data 1207a that
is stored in the memory 1205. When the processor 1203 executes the
instructions 1209a, various portions of the instructions 1209b may
be loaded onto the processor 1203, and various pieces of data 1207b
may be loaded onto the processor 1203.
[0088] The wireless communication device 1204 may also include a
transmitter 1211 and a receiver 1213 to allow transmission and
reception of signals to and from the wireless communication device
1204. The transmitter 1211 and receiver 1213 may be collectively
referred to as a transceiver 1215. An antenna 1217 may be
electrically coupled to the transceiver 1215. The wireless
communication device 1204 may also include (not shown) multiple
transmitters, multiple receivers, multiple transceivers and/or
additional antennas.
[0089] The wireless communication device 1204 may include a digital
signal processor (DSP) 1221. The wireless communication device 1204
may also include a communications interface 1223. The
communications interface 1223 may allow a user to interact with the
user equipment (UE) 1204.
[0090] The various components of the wireless communication device
1204 may be coupled together by one or more buses, which may
include a power bus, a control signal bus, a status signal bus, a
data bus, etc. For the sake of clarity, the various buses are
illustrated in FIG. 12 as a bus system 1219.
[0091] FIG. 13 illustrates certain components that may be included
within a base station 1302. A base station 1302 may also be
referred to as, and may include some or all of the functionality
of, an access point, a broadcast transmitter, a NodeB, an evolved
NodeB, etc. The base station 1302 includes a processor 1303. The
processor 1303 may be a general purpose single- or multi-chip
microprocessor (e.g., an ARM), a special purpose microprocessor
(e.g., a digital signal processor (DSP)), a microcontroller, a
programmable gate array, etc. The processor 1303 may be referred to
as a central processing unit (CPU). Although just a single
processor 1303 is shown in the base station 1302 of FIG. 13, in an
alternative configuration, a combination of processors (e.g., an
ARM and DSP) could be used.
[0092] The base station 1302 also includes memory 1305. The memory
1305 may be any electronic component capable of storing electronic
information. The memory 1305 may be embodied as random access
memory (RAM), read-only memory (ROM), magnetic disk storage media,
optical storage media, flash memory devices in RAM, on-board memory
included with the processor, EPROM memory, EEPROM memory, registers
and so forth, including combinations thereof.
[0093] Data 1307a and instructions 1309a may be stored in the
memory 1305. The instructions 1309a may be executable by the
processor 1303 to implement the methods disclosed herein. Executing
the instructions 1309a may involve the use of the data 1307a that
is stored in the memory 1305. When the processor 1303 executes the
instructions 1309a, various portions of the instructions 1309b may
be loaded onto the processor 1303, and various pieces of data 1307b
may be loaded onto the processor 1303.
[0094] The base station 1302 may also include a transmitter 1311
and a receiver 1313 to allow transmission and reception of signals
to and from the base station 1302. The transmitter 1311 and
receiver 1313 may be collectively referred to as a transceiver
1315. An antenna 1317 may be electrically coupled to the
transceiver 1315. The base station 1302 may also include (not
shown) multiple transmitters, multiple receivers, multiple
transceivers and/or additional antennas.
[0095] The base station 1302 may include a digital signal processor
(DSP) 1321. The base station 1302 may also include a communications
interface 1323. The communications interface 1323 may allow a user
to interact with the base station 1302.
[0096] The various components of the base station 1302 may be
coupled together by one or more buses, which may include a power
bus, a control signal bus, a status signal bus, a data bus, etc.
For the sake of clarity, the various buses are illustrated in FIG.
13 as a bus system 1319.
[0097] The term "determining" encompasses a wide variety of actions
and, therefore, "determining" can include calculating, computing,
processing, deriving, investigating, looking up (e.g., looking up
in a table, a database or another data structure), ascertaining and
the like. Also, "determining" can include receiving (e.g.,
receiving information), accessing (e.g., accessing data in a
memory) and the like. Also, "determining" can include resolving,
selecting, choosing, establishing and the like.
[0098] The phrase "based on" does not mean "based only on," unless
expressly specified otherwise. In other words, the phrase "based
on" describes both "based only on" and "based at least on."
[0099] No claim element is to be construed under the provisions of
35 U.S.C. .sctn.112, sixth paragraph, unless the element is
expressly recited using the phrase "means for" or, in the case of a
method claim, the element is recited using the phrase "step
for."
[0100] The term "processor" should be interpreted broadly to
encompass a general purpose processor, a central processing unit
(CPU), a microprocessor, a digital signal processor (DSP), a
controller, a microcontroller, a state machine and so forth. Under
some circumstances, a "processor" may refer to an application
specific integrated circuit (ASIC), a programmable logic device
(PLD), a field programmable gate array (FPGA), etc. The term
"processor" may refer to a combination of processing devices, e.g.,
a combination of a DSP and a microprocessor, a plurality of
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration.
[0101] The term "memory" should be interpreted broadly to encompass
any electronic component capable of storing electronic information.
The term memory may refer to various types of processor-readable
media such as random access memory (RAM), read-only memory (ROM),
non-volatile random access memory (NVRAM), programmable read-only
memory (PROM), erasable programmable read-only memory (EPROM),
electrically erasable PROM (EEPROM), flash memory, magnetic or
optical data storage, registers, etc. Memory is said to be in
electronic communication with a processor if the processor can read
information from and/or write information to the memory. Memory
that is integral to a processor is in electronic communication with
the processor.
[0102] The terms "instructions" and "code" should be interpreted
broadly to include any type of computer-readable statement(s). For
example, the terms "instructions" and "code" may refer to one or
more programs, routines, sub-routines, functions, procedures, etc.
"Instructions" and "code" may comprise a single computer-readable
statement or many computer-readable statements.
[0103] The functions described herein may be implemented in
software or firmware being executed by hardware. The functions may
be stored as one or more instructions on a computer-readable
medium. The terms "computer-readable medium" or "computer-program
product" refers to any tangible storage medium that can be accessed
by a computer or a processor. By way of example, and not
limitation, a computer-readable medium may include RAM, ROM,
EEPROM, CD-ROM or other optical disk storage, magnetic disk storage
or other magnetic storage devices, or any other medium that can be
used to carry or store desired program code in the form of
instructions or data structures and that can be accessed by a
computer. Disk and disc, as used herein, includes compact disc
(CD), laser disc, optical disc, digital versatile disc (DVD),
floppy disk and Blu-ray.RTM. disc where disks usually reproduce
data magnetically, while discs reproduce data optically with
lasers. It should be noted that a computer-readable medium may be
tangible and non-transitory. The term "computer-program product"
refers to a computing device or processor in combination with code
or instructions (e.g., a "program") that may be executed, processed
or computed by the computing device or processor. As used herein,
the term "code" may refer to software, instructions, code or data
that is/are executable by a computing device or processor.
[0104] Software or instructions may also be transmitted over a
transmission medium. For example, if the software is transmitted
from a website, server, or other remote source using a coaxial
cable, fiber optic cable, twisted pair, digital subscriber line
(DSL), or wireless technologies such as infrared, radio and
microwave, then the coaxial cable, fiber optic cable, twisted pair,
DSL, or wireless technologies such as infrared, radio and microwave
are included in the definition of transmission medium.
[0105] The methods disclosed herein comprise one or more steps or
actions for achieving the described method. The method steps and/or
actions may be interchanged with one another without departing from
the scope of the claims. In other words, unless a specific order of
steps or actions is required for proper operation of the method
that is being described, the order and/or use of specific steps
and/or actions may be modified without departing from the scope of
the claims.
[0106] Further, it should be appreciated that modules and/or other
appropriate means for performing the methods and techniques
described herein, such as those illustrated by FIGS. 9-10, can be
downloaded and/or otherwise obtained by a device. For example, a
device may be coupled to a server to facilitate the transfer of
means for performing the methods described herein. Alternatively,
various methods described herein can be provided via a storage
means (e.g., random access memory (RAM), read-only memory (ROM), a
physical storage medium such as a compact disc (CD) or floppy disk,
etc.), such that a device may obtain the various methods upon
coupling or providing the storage means to the device. Moreover,
any other suitable technique for providing the methods and
techniques described herein to a device can be utilized.
[0107] It is to be understood that the claims are not limited to
the precise configuration and components illustrated above. Various
modifications, changes and variations may be made in the
arrangement, operation and details of the systems, methods and
apparatus described herein without departing from the scope of the
claims.
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